For texture intensive scenes, we strongly encourage the use of tiled/mip mapped textures files with the streamed map file texture.
An internal stress test show than you can keep full interativity in the 3D view with 576 maps (8k for each) loaded from a portable usb drive, consuming only what you set in the preference for the cache (500mo in this test).
You can convert your maps with the supplied maketx utility, which create tiled tiffs or exr , depending on the source, if your 2D application can't save tiled formats (be carefull, photoshop and mari's tiff for example, are not compatible with streaming.. you must convert them before use in the stream map file).